Glock Inc uses the 17lb single stage recoil spring in all its "full sized" 9/40/357/45GAP/10mm/45ACP pistols. You don’t have to be a rocket scientist to comprehend the performance of a single spring weight is BOUND to VARY when used across a broad range of calibers & bullet weights.
Many of our customers have found the 20lb & 22lb recoil spring enhances the performance of their G20.
Its easy to change recoil spring weights. You can see a selection of GR & springs here http://www.lonewolfdist.com/Search.aspx?TERM=lwd-gr